Linear condensation polymers of bis-(phosphine) decaboranes



United States Patent Schroeder, New Haven, Comm, assignors to Olin 5 Mathieson Chemical Corporation, a corporation of Virginia No Drawing. Filed June 28, 1962, Ser. No. 205,862

8 Claims. (Cl. 2602) This invention relates to the preparation of linear polymers by the condensation of bis(halodiarylphosphine) decaboranes with bis(hydroxydiarylphosphine) decaboranes. More particularly, it relates to linear polymers formed by the condensation of approximately equal molar amounts of bis(chlorodiarylphosphine) decaboranes and bis(hydroxydiarylphosphine) decaboranes.

Although the structural formula of the linear polymers of this invention has not been definitely established one possible mechanism for the preparation of these novel polymeric materials can be illustrated by the following equation.

In the above equation n is about 5 to 100 or more and R is an aryl radical selected from the group consisting of phenyl, tolyl, xylyl, naphthyl and biphenylyl and R is an alkyl radical having from 1 to 5 carbon atoms in the alkyl group. The novel polymers of this invention can be prepared by the condensation of bis(hydroxydiarylphosphine) decaboranes with a bis(chlorodiarylphosphine) decaborane in approximately equal molar proportions at temperatures ranging from about 60 to 220 C. in the presence of a tri(lower alkyl)amine. The reaction can be carried out, for example, by adding a solution of dry tri(lower alkyl) amine in an inert organic solvent to a suspension of bis(chlorodiarylphosphine) decaborane and bis(hydroxydiarylphosphine) decaborane in an inert organic solvent and heating the resulting reaction mixture to a temperature of from 60 C. to 220 C. Alternatively, the amine solution can be added to a refluxing suspension of the two reactants in an inert organic solvent. The polymerization reaction is carried out while the reactants are in admixture with an inert organic solvent.

The reaction time generally will be from about 0.5 to 5 hours or more depending upon the particular solvent and other reaction conditions employed.

Suitable solvents for use in the preparation of novel polymers of this invention include benzene, toluene, xylene decaline, dioxane, carbon tetrachloride, etc. The proportion of solvent employed is not critical and may range from about 1 to about parts or more by weight per part of the reactants used. Tri(lower alkyl) amines useful in this invention include trimethyl amine, triethyl amine, methyl diethyl amine, tri-isopropyl amine, tributyl amine and triisoamyl amine, etc. The presence of the tri(lower alkyl) amine is essential in the process of this invention. Without the addition of a tri(lower alkyl) amine, the compounds bis(chlorodiphenylphosphine) decaborane and bis(hydroxydiphenylphosphine) decaborane do not react to form polymers even under refluxing conditions and from such a reaction the starting materials are recovered unchanged. In addition, the amine serves to bind the hydrogen chloride set free during the polymerization thus causing the reaction to proceed to completion. Generally the molar amount of the amine employed will be equal to two times the number of moles of the bis- (chlorodiphenylphosphine) decaborane charged to the reactor although an excess of the amine up to about 3 or 4 moles or more of amine per mole of the bis(chlorodiphenylphosphine) decaborane can be employed, if desired.

The bis(chlorodiarylphosphine) decaboranes utilized as starting materials in the process of this invention can be prepared by the process set forth in Heying and Schroeder application Serial No. 205,859, for Product and Method, filed June 28, 1962. The compound bis(chlorodiphenylphosphine) decaborane is prepared, for example, by reacting a solution of diphenylchlorophosphine in ether with a solution of decaborane in ether for about 2 hours at 25 C. and recovering the resulting product from the reaction mixture.

Other useful bis(chlorodiarylphosphine) decaboranes include, bis(chlorodiphenylphosphine) decaborane, bis- (chlorodinaphthylphosphine) decaborane, bis(chloroditolylphosphine) decaborane, bis(chlorodixylylphosphine) decaborane, bis(chlorodiethylphenylphosphine) decabo-.

rane, bis(chlorodimethylnaphthylphosphine) decaborane, etc.

Bis(hydroxydiarylphosphine) decaboranes useful as starting materials in the preparation of the novel polymers of this invention include, for example, bis(hydroxydiphenylphosphine) decaborane, bis(hydroxyditolylphosphine) decaborane, bis(hydroxydixylylphosphine) decaborane, bis(hydroxydiisopropylphenylphosphine) decaborane, and bis(hydroxydi-n-butyltolylphosphine) decaborane. Bis(hydroxydiarylphosphine) decaboranes can be prepared in the manner described and claimed in Schroeder application Serial No. 205,860, for Process, filed June 28, 1952. According to the method described in this application bis(hydroxydiphenylphosphine) decaborane can be prepared by reacting bis(chlorodiphenylphosphine) dissolved in acetone with a stoichiometric excess of Water.

The polymeric product, which precipitates from the inert organic solvent utilized in the reaction, can be separated from the reaction mixture by a wide variety of methods well known to the arts such as by filtration, decantation, etc.

The polymers of this invention are insoluble in most common organic solvents such as acetone, ligroin, alcohols, chloroform, and xylene. Molecular weight determinations made by light scattering methods in N-methylpyrrolidone solution gave values as high as about 27,000. Polymers produced by the process of this invention do not melt upon heating but start to evolve hydrogen at about 270 C. and when heated up to 400 C. a product remains which is insoluble in any of the solvents investigated which included dimethylformamide, nitromethane, dimethylsulfioxide, and N-methylpyrrolidone. Films which are useful as protective coatings for metal objects in high temperature service can be formed from the polymeric products of this invention. A solution of the polymer in a suitable solvent, such as methyl pyrrolidone can be applied to the object by dipping or brushing and a protective film formed by evaporation of the solvent. These valuable polymers are useful for the preparation of a wide variety of products because of their excellent heat resistance and extreme resistance to solvent action. For example, such polymers can ,be incorporated into phenol-formaldehyde or urea-formaldehyde plastics to increase the high temperature stability and solvent resistance of such products.

This invention is illustrated in detail by the following examples.

EXAMPLE I Bis(chlorodiphenylphosphine) decaborane (5.0 g., .009 mole) and bis(hydroxydiphenylphosphine) decaborane (4.7 g., .009 mole) were mixed in a dry flask. A solution of 1.818 g., (.018 mole) dry triethylamine in 50 ml. dry

. ea benzene was added very slowly with stirring. After the addition, which required about 45 minutes, the mixture was refluxed for an hour and then filtered. The residue was washed first with cold acetone, then water and finally 3.7 g. (73 percent of the theoretical amount) of polymeric product. The product was shown by its IR spectrum to be the same type of polymer as produced in Example I.

with hot' acetone.f A white polymeric product (M.P. EXAMPLE XI i300; .t)y;'ema1ned (7.85 g., 87 P r Of the theorem Dry triethylamine (2.02 g., 0.02 mole) dissolved in anq 1 I V hydrous dioxane (50 ml.) was added, with stirring, to a Calcd for CMEBZBIOOKZ: 56x89; 2136; suspension of bis(chlorodiphenylphosphine) decaborane Found 11,111. (5.61 g., 0.01 mole) and bis(hydroxydiphenylphosphine) 1O decaborane (5.23 0.01 mole) in anh drous 14-diox- EXAMPLES II-VI Y ane (100 ml.) over a period of 20 minutes. Then the A number of adidtional experiments were performed in mixture was refluxed for one hour and filtered. The resithe same manner as described in Example I. Pertinent due was washed thoroughly with acetone, water, and data relating to these experiments is included in Table finally with hot acetone. A white polymer remained I which follows, 15 (M.P. 300); yield: 7.9 g. (78 percent of the theoreti- Table l Reactor Charge Yield of Polymer Addition Reflux Example 7 Bis(Chlorodi- Bis(Hydroxy- Triethyl Period Period phenylphosdiphenylphos- Amine (Minutes) (Minutes) (Grams) (Percent) phine) Dccaphiue) Deca- (Mole) borane (Mole) borane (Mole) 1 Dissolved in 30 ml. of dry benzene.

EXAMPLE VII cal quantity). The product was identified by its IR spec- A Solution of 21 (002 mole) of triethylamine trum which was identical with that of the product of (dried over KOH) in anhydrous benzene (50 ml.) was Example added, with stirring, to a suspension of bis(chlorodiphen- EXAMPLE XII ylphosphine) decaborane (5.6 g., 0.01 mole) and bis(hydroxydiphenylphosphine) decaborane (5.2 g., 0.01 mole) (A) An 8.4 percent solution in N-methylpyrrolidone in anhydrous benzene ml.) over a period of 15 minof the polymeric product prepared by reacting substanutes. After the addition had been completed, the mixture tially equimolar proportions of bis(chlorodipheny1phoswas refluxed for one hour and then filtered. The residue 40 phine) decaborane and bis(hydroxydiphenylphosphine) was eXtTacted Wlth f and hot acetone to remove decaborane in the presence of triethylamine, was applied Y'P 5 Yleldmg Percent of the to an anodized aluminum plate and evaporated at 300 ggggi g amount) of the Polymer1c product M' F. A clear, continuous, adhesive film was formed which 7 was resistant to impact and bending. P ig g i g g gi (B) A paste consisting of 66 percent by weight of a phenolformaldehyde resin of phenol-novolak type (in alco- EXAMPLES VIH-IX holic solution), 33 percent by weight of the polymeric Examples 111 and 1 hi were carried out in the product prepared as described in Part A of this example same manner as described in Example VII are reported and 1 Percent Of hexamethylenetetfamine a Curing in Table 2 which follows. agent) was brushed on and between anodized aluminum Table 2 Reactor Charge Yield of Polymer Addition Reflux Example Bis(Ohlorodi- Bis(Hydr0xy- Triethyl Period Period phenylphosdiphenylphos- Amine (Minutes) (Minutes) (Grams) (Percent) phine) Decaphine) Deea- (Mole) borane (Mole) borane (Mole) VIII 0. 01 0. 01 0.02 45 8.4 83 IX 0. 005 0. 005 1 0. 01 30 60 4. 3 s5 1 Dissolved in 50 ml. of dry benzene. 2 Dissolved in 25 ml. of dry benzene.

EXAMPLE X plates and the solvents were then evaporatedby heating CA solution of 1 g. (0.01 mole) of dry triethylamine in fi lprePared lilates at for i on anhydrous benzene (30 ml.) was added, with stirring, to t e a ummum p atejs a comlimous ad eslve film was a suspension of bis(chlorodiphenylphosphine) decaborane demonsu'au ng the 9 of the boron (28 g 0005 mole) and bis(hydroxydiphenylphosphine) contaim ne polymer into the phenol c resin. Furthermore, decaborane (2.6 g., 0.005 -mole) in anhydrous benzene the addmfm of the .boroll'contalnmg P y enhanced (40 1 D i th ddi i i d (20 i the the adheslve properties of the phenolic resin in the metal mixture was refluxed (bath temperature 95 C.), and was to metal bond. then kept refluxing for another hour. The reaction prod- What is claimed is:

not was worked up as described in Example VII to yield 1. The linear polymeric condensation products of the condensation of substantially equimolar proportions of a compound of the formula:

wherein R is an aryl radical selected from the group consisting of phenyl, tolyl, xylyl, naphthyl and biphenylyl, with a material of the formula:

wherein R is an aryl radical selected from the group consisting of phenyl, tolyl, xylyl, naphthyl and biphenyl with an approximately equal molar amount of a material of the formula:

R R OHI BH z(-]. OH

wherein R has the same meaning as previously defined, in the presence of a tri(lower alkyl) amine and at a temperature of from about C. to about 200 C., while the reactants are in admixture with an inert organic solvent.

4. The process of claim 3 wherein the said compound is bis(chlorodiphenylphosphine) decaborane.

5. The process of claim 2 wherein the said material is bis(hydroxydiphenylphosphine) decaborane.

6. The process of claim 2 wherein the said tri(lower alkyl) amine is triethyl amine.

7. The process of claim 3 wherein the said inert organic solvent is benzene.

8. The process for the preparation of a linear polymeric condensation product which comprises reacting bis (chlorodiphenylphosphine) decaborane with an approximately equal molar quantity of bis(hydroxydiphenylphosphine) decaborane in the presence of triethyl amine and at a temperature of from about 60 C. to about 200 C. while the reactants are in admixture with an inert organic solvent.

References Cited in the file of this patent UNITED STATES PATENTS 3,071,552 Burg Jan. 1, 1963 

1. THE LINEAR POLYMERIC CONDENSATION PRODUCTS OF THE CONDENSATION OF SUBSTANTIALLY EQUIMOLAR PROPORTIONS OF A COMPOUND OF THE FORMULA: 